JPWO2020054848A1 - Method for manufacturing resin composition, molded product, secondary processed product and resin composition - Google Patents

Abstract

A resin composition having good gas barrier properties, retort resistance and long-run properties, and excellent hue and film thickness stability during continuous melt molding, a molded product and a secondary processed product containing this resin composition, and this resin composition. Provide a method for manufacturing a product. It contains an ethylene-vinyl alcohol copolymer (A), a polyamide resin (B), an alkaline earth metal salt (C) and an alkali metal salt (D), and contains an ethylene-vinyl alcohol copolymer (A) and a polyamide resin (B). ) Is 55/45 to 99/1, and the alkaline earth metal salt (C) with respect to the total amount of the ethylene-vinyl alcohol copolymer (A) and the polyamide resin (B). ) Is contained in an amount of 10 to 200 ppm in terms of metal atom, and the ratio (Dm / Cm) of the mass (Dm) of the alkali metal salt (D) in terms of metal atom to the mass (Cm) of the alkaline earth metal salt (C) in terms of metal atom. ) Is 1 to 20.

Description

The present invention relates to a resin composition, a molded product, a secondary processed product, a method for producing a resin composition, and a method for producing a molded product.

Ethylene-vinyl alcohol copolymer (hereinafter, may be abbreviated as "EVOH") is a resin having an excellent barrier property against oxygen, odor, flavor and the like. Therefore, EVOH is suitably used as a packaging material for foods and the like. In the field of packaging materials such as foods, heat treatment (retort treatment or boiling treatment) with hot water or steam is often performed after filling the contents of foods or the like. When a packaging material containing EVOH is heat-treated with hot water or steam for a long time, there is a disadvantage that whitening streaks and partial white turbidity (whitening, etc.) occur and the appearance deteriorates. It has been done. For example, Patent Document 1 comprises EVOH, a polyamide resin (hereinafter sometimes abbreviated as "PA"), and an aliphatic carboxylic acid magnesium salt having 6 or less carbon atoms, and PA and a fat having 6 or less carbon atoms in EVOH. A film using resin composition pellets in which a magnesium group carboxylic acid salt is finely dispersed is disclosed as a film having an excellent appearance after heat treatment. In Patent Document 2, when a multilayer pellet having a layer containing EVOH as a main component containing a metal salt and a layer containing PA as a main component is used, it is excellent in thermal stability during long-run melt molding, and after heat treatment. It is disclosed that a film having an excellent appearance can be obtained.

International Publication No. 2015/174396 Japanese Unexamined Patent Publication No. 2009-242591

Both the films disclosed in Patent Document 1 and Patent Document 2 are resin compositions containing EVOH and PA. When such a resin composition containing EVOH and PA is melt-molded, a gel predicted to be mainly caused by the reaction between EVOH and PA may be produced, and the obtained multilayer structure may be lumpy. Although the resin composition described in Patent Document 1 is described to be excellent in thermal stability during film formation, a resin composition having more excellent long-running property is required. Further, although it is described that the resin composition described in Patent Document 2 is excellent in thermal stability during long-run melt molding, it may be after heat treatment (after retort treatment) depending on the melt-kneading conditions at the time of molding. Partial white turbidity and whitening streaks may occur, and while the long-running property is improved, the appearance characteristics after the retort treatment may be deteriorated. Therefore, there is a demand for a resin composition containing EVOH and PA, which can stably produce a film having an excellent appearance after retort treatment (retort resistance) and having more excellent long-running properties.

An object of the present invention is a resin composition having good gas barrier properties, retort resistance and long-run properties, and excellent hue and film thickness stability during continuous melt molding, a molded product containing the resin composition, and secondary processing. The present invention is to provide an article and a method for producing the resin composition.

According to the present invention, the above object includes [1] ethylene-vinyl alcohol copolymer (A), polyamide resin (B), alkaline earth metal salt (C) and alkali metal salt (D), and ethylene-. The mass ratio (A / B) of the vinyl alcohol copolymer (A) to the polyamide resin (B) is 55/45 to 99/1, and the ethylene-vinyl alcohol copolymer (A) and the polyamide resin (B) Contains 10 to 200 ppm of the alkaline earth metal salt (C) in terms of metal atom, and the metal of the alkali metal salt (D) with respect to the mass (Cm) of the alkaline earth metal salt (C) in terms of metal atom. A resin composition having an atomic equivalent mass (Dm) ratio (Dm / Cm) of 1 to 20 and satisfying the following requirement 1 (requirement 1).
When a film having a thickness of 20 μm made of the resin composition is continuously formed at 230 ° C. using a single-screw extruder, it is visually observed in the film formed one hour after the start of film formation. Of the defects, the number of defects having an alkaline earth metal concentration of 0.1 at% or more is less than two;
[2] The resin composition of [1], wherein the metal constituting the alkaline earth metal salt (C) contains magnesium or calcium;
[3] The resin composition of [1] or [2], wherein the metal constituting the alkali metal salt (D) contains sodium or potassium;
[4] The resin composition according to any one of [1] to [3], wherein the alkaline earth metal salt (C) is an aliphatic carboxylic acid alkaline earth metal salt having 6 or less carbon atoms;
[5] The resin composition according to any one of [1] to [4], wherein the alkali metal salt (D) is an aliphatic carboxylic acid alkali metal salt having 6 or less carbon atoms;
[6] The resin composition according to any one of [1] to [5], wherein the polyamide resin (B) contains nylon 6.
[7] The resin composition according to any one of [1] to [6], which is in the form of pellets;
[8] A molded product containing the resin composition according to any one of [1] to [7];
[9] The molded product of [8], which is a film;
[10] The molded product of [8] or [9], which is a retort-treated packaging material or a boil-treated packaging material;
[11] Secondary processed product of the molded product according to any one of [8] to [10];
[12] A step of immersing at least one of the ethylene-vinyl alcohol copolymer (A) and the polyamide resin (B) in an aqueous solution containing an alkaline earth metal salt (C) and an alkali metal salt (D), and an ethylene-vinyl The method for producing a resin composition according to any one of [1] to [7], which comprises a step of melt-kneading the alcohol copolymer (A) and the polyamide resin (B);
[13] The step of mixing a molten resin containing an ethylene-vinyl alcohol copolymer (A) and a polyamide resin (B) with an aqueous solution containing an alkaline earth metal salt (C) and an alkali metal salt (D) is included. , The method for producing the resin composition according to any one of [1] to [7];

According to the present invention, a resin composition having good gas barrier properties, retort resistance and long-run properties, and excellent hue and film thickness stability during continuous melt molding, a molded product containing the resin composition and secondary processing. A product, and a method for producing the resin composition and a molded product can be provided.

Hereinafter, the present invention will be described in detail. The gas barrier property in the present specification is based on the measurement result of the oxygen barrier property. Further, the long-run property refers to a property that even if melt molding is continued for a long period of time, a molded product with less lumps and a good appearance can be obtained.

<Resin composition>
The resin composition of the present invention includes ethylene-vinyl alcohol copolymer (A) (hereinafter, may be abbreviated as "EVOH (A)"), polyamide (B) (hereinafter, "PA (B)"). (May be abbreviated), contains alkaline earth metal salt (C) and alkali metal salt (D), and has a mass ratio (A / B) of EVOH (A) to PA (B) of 55/45 to 99 /. It is 1, and contains 10 to 200 ppm of alkaline earth metal salt (C) in terms of metal atom with respect to the total amount of EVOH (A) and PA (B), and is converted into metal atom of alkaline earth metal salt (C). The ratio (Dm / Cm) of the mass (Dm) of the alkali metal salt (D) in terms of metal atom to the mass (Cm) is 1 to 20, and the following requirement 1 is satisfied.
(Requirement 1)
When a film having a thickness of 20 μm made of the resin composition is continuously formed at 230 ° C. using a single-screw extruder, it is visually observed in the film formed one hour after the start of film formation. Among the defects, the number of defects in which the concentration of the alkaline earth metal is 0.1 at% or more is less than two.

<EVOH (A)>
By containing EVOH (A) in the resin composition of the present invention, the gas barrier property of the obtained molded product can be enhanced. EVOH (A) is usually obtained by saponifying an ethylene-vinyl ester copolymer. That is, EVOH (A) is usually a saponified product of an ethylene-vinyl ester copolymer. The copolymerization of ethylene and vinyl ester and the saponification of the ethylene-vinyl ester copolymer can be carried out by a known method. Vinyl acetate is a typical vinyl ester, but other vinyl esters such as fatty acid vinyl esters (vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate and versatic) (Vinyl acetate, etc.) may be used.

The lower limit of the degree of saponification of EVOH (A) is preferably 85 mol%, more preferably 90 mol%, further preferably 96 mol%, particularly preferably 98 mol%, and most preferably 99 mol%. When the lower limit of the degree of saponification is 85 mol% or more, the gas barrier property of the molded product can be enhanced. The upper limit of the degree of saponification may be 100 mol% or 99.99 mol%.

The lower limit of the ethylene unit content in EVOH (A) is preferably 5 mol%, more preferably 10 mol%, further preferably 20 mol%, and particularly preferably 25 mol%. The upper limit of the ethylene unit content is preferably 70 mol%, more preferably 50 mol%, further preferably 40 mol%, even more preferably 35 mol%, and particularly preferably 30 mol%. When the ethylene unit content is 5 mol% or more, the appearance of the film or the like after heat treatment and the long-run property at the time of melt molding can be improved. On the other hand, when the ethylene unit content is 70 mol% or less, the gas barrier property can be enhanced in a film or the like.

Further, EVOH (A) may have a unit derived from a monomer other than ethylene, vinyl ester and a saponified product thereof, as long as the object of the present invention is not impaired. When EVOH (A) has units derived from other monomers, the content of the other monomer units with respect to the total structural units of EVOH (A) is preferably 30 mol% or less, more preferably 20 mol% or less. It is more preferably 10 mol% or less, and particularly preferably 5 mol% or less. When EVOH (A) contains other monomer units, it is also possible to adjust the melting point by adjusting the content thereof. When EVOH (A) contains a unit derived from another monomer, the lower limit thereof may be 0.05 mol% or 0.10 mol%. Examples of the other monomer include unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid and itaconic acid or anhydrides, salts thereof, mono or dialkyl esters and the like; nitriles such as acrylonitrile and methacrylnitrile; acrylamide. Amides such as methacrylamide; olefin sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid, and metaallyl sulfonic acid or salts thereof; vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tri (β-methoxy-ethoxy) silane, γ- Vinyl silane compounds such as methacryloxypropyl methoxysilane; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride and the like can be mentioned.

Further, the units derived from other monomers are the structural unit (I) represented by the following general formula (I), the structural unit (II) represented by the following general formula (II), and the following general formula (III). It may be at least one of the structural units (III) represented by. When EVOH (A) has such a structural unit, the bending resistance of the obtained film or the like can be further enhanced.

In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are independently hydrogen atoms and 1 to 10 carbon atoms. It represents an aliphatic hydrocarbon group, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group. Further, a pair of ^{R 1} , R ² and R ^{3 , R 4} and R ⁵ , and R ⁶ and R ⁷ may be combined. In addition, some or all of the hydrogen atoms of the above-mentioned aliphatic hydrocarbon group having 1 to 10 carbon atoms, alicyclic hydrocarbon group having 3 to 10 carbon atoms, and aromatic hydrocarbon group having 6 to 10 carbon atoms are included. It may be substituted with a hydroxyl group, an alkoxy group, a carboxyl group or a halogen atom. R ¹² and R ¹³ independently represent a hydrogen atom, a formyl group, or an alkanoyl group having 2 to 10 carbon atoms.

In the structural unit (I), (II) or (III), examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms include an alkyl group and an alkenyl group, and an alicyclic hydrocarbon group having 3 to 10 carbon atoms. Examples thereof include a cycloalkyl group and a cycloalkenyl group, and examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms include a phenyl group and the like.

In the structural unit (I), R ¹ , R ² and R ³ are preferably hydrogen atoms, methyl groups, ethyl groups, hydroxyl groups, hydroxymethyl groups and hydroxyethyl groups, respectively, and among them, the resin of the present invention. From the viewpoint of further improving the stretchability and thermoformability of the composition, it is more preferable that the composition is independently a hydrogen atom, a methyl group, a hydroxyl group and a hydroxymethyl group.

The method of containing the structural unit (I) in the EVOH (A) is not particularly limited, and examples thereof include a method of copolymerizing a monomer derived to the structural unit (I) in the polymerization of ethylene and vinyl ester. .. Examples of such monomers include alkenes such as propylene, butylene, pentene, and hexene; 3-hydroxy-1-propene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3, 4-Diacyloxy-1-butene, 3-acidoxy-4-hydroxy-1-butene, 4-acyloxy-3-hydroxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2- Methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diasiloxy-2-methyl-1-butene, 4-hydroxy-1-pentene, 5-hydroxy-1-pentene, 4, 5-Dihydroxy-1-pentene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diasiloxy-1-pentene, 4-hydroxy-3-methyl-1-pentene, 5-hydroxy- 3-Methyl-1-pentene, 4,5-dihydroxy-3-methyl-1-pentene, 5,6-dihydroxy-1-hexene, 4-hydroxy-1-hexene, 5-hydroxy-1-hexene, 6- Alkenes having hydroxyl groups or ester groups such as hydroxy-1-hexene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-hexene, 5,6-diasiloxy-1-hexene and the like can be mentioned. Be done. Among them, from the viewpoint of copolymerization reactivity and gas barrier property of the obtained film or the like, propylene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, 3,4- Diacyloxy-1-butene is preferred. Asyloxy is preferably acetoxy, and specifically, 3-acetoxy-1-propene, 3-acetoxy-1-butene, 4-acetoxy-1-butene and 3,4-diacetoxy-1-butene are preferable. In the case of an alkene having an ester, it is derived to the structural unit (I) during the saponification reaction.

In the structural unit (II), it is preferable that both ^{R 4} and R ^{5 are hydrogen atoms.} In particular, ^{it is more preferable that both R 4} and R ⁵ are hydrogen atoms, one of R ⁶ and R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and the other is a hydrogen atom. The aliphatic hydrocarbon group is preferably an alkyl group or an alkenyl group. From the viewpoint of particularly placing importance on the gas barrier property of the obtained film or the like, ^{it is particularly preferable that one of R 6} and R ⁷ is a methyl group or an ethyl group and the other is a hydrogen atom. Further, one of ^{R 6} and R ⁷ _{is a substituent represented by (CH 2} ) _h OH (however, h is an integer of 1 to 8 and h is preferably an integer of 1 to 4). It is more preferably 1 or 2), and it is also particularly preferable that the other is a hydrogen atom.

The method for containing the structural unit (II) in EVOH (A) is not particularly limited. For example, a method of reacting EVOH (A) obtained by a saponification reaction with a monovalent epoxy compound represented by the following general formulas (IV) to (X) is preferably used.

In the formula, R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ are independently hydrogen atoms, aliphatic hydrocarbon groups having 1 to 10 carbon atoms (alkyl groups, alkenyl groups, etc.), and carbon atoms 3 to 3. It represents 10 alicyclic hydrocarbon groups (cycloalkyl group, cycloalkenyl group, etc.) or an aliphatic hydrocarbon group having 6 to 10 carbon atoms (phenyl group, etc.). Further, i, j, k, p and q each independently represent an integer of 1 to 8. However, when R ¹⁷ is a hydrogen atom, R ¹⁸ has a substituent other than the hydrogen atom.

Examples of the monovalent epoxy compound represented by the general formula (IV) include epoxyethane (ethylene oxide), epoxypropane, 1,2-epoxybutane, 2,3-epoxybutane, and 3-methyl-1,2-epoxy. Butane, 1,2-epoxypentane, 3-methyl-1,2-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 3-methyl-1,2-epoxy Hexane, 3-methyl-1,2-epoxy heptane, 4-methyl-1,2-epoxy heptane, 1,2-epoxy octane, 2,3-epoxy octane, 1,2-epoxy nonane, 2,3-epoxy Examples thereof include nonane, 1,2-epoxydecane, 1,2-epoxydodecane, epoxyethylbenzene, 1-phenyl-1,2-epoxypropane, 3-phenyl-1,2-epoxypropane and the like.

Examples of the monovalent epoxy compound represented by the general formula (V) include various alkyl glycidyl ethers. Examples of the monovalent epoxy compound represented by the general formula (VI) include various alkylene glycol monoglycidyl ethers. Examples of the monovalent epoxy compound represented by the general formula (VII) include various alkenyl glycidyl ethers. Examples of the monovalent epoxy compound represented by the general formula (VIII) include various epoxy alkanols such as glycidol. Examples of the monovalent epoxy compound represented by the general formula (IX) include various epoxy cycloalkanes. Examples of the monovalent epoxy compound represented by the general formula (X) include various epoxy cycloalkenes.

Among the monovalent epoxy compounds, an epoxy compound having 2 to 8 carbon atoms is preferable. In particular, from the viewpoint of ease of handling of the compound and reactivity, the monovalent epoxy compound preferably has 2 to 6 carbon atoms, more preferably 2 to 4 carbon atoms. Further, the monovalent epoxy compound is particularly preferably a compound represented by the general formula (IV) and a compound represented by (V) among the above general formulas, and the reactivity with EVOH (A) and the obtained film. From the viewpoint of gas barrier properties such as 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, epoxyethane and glycidol are preferable, and epoxypropane and glycidol are particularly preferable.

In structural unit (III), R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are hydrogen atoms or methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups and n. -It is preferably an aliphatic hydrocarbon group having 1 to 5 carbon atoms such as a pentyl group.

The method for containing the structural unit (III) in EVOH (A) is not particularly limited, and examples thereof include the methods described in JP-A-2014-0346447.

The lower limit of the melting point TmA of EVOH (A) is preferably 160 ° C., more preferably 170 ° C., even more preferably 180 ° C., and particularly preferably 185 ° C. On the other hand, the upper limit of the melting point TmA is preferably 210 ° C., more preferably 200 ° C., and even more preferably 195 ° C. When the melting point TmA of EVOH (A) is within the above range, long-running property, gas barrier property, retort resistance, etc. at the time of melt molding can be further improved.

The melt viscosity of EVOH (A) is preferably such that the lower limit of MFR under the condition of 210 ° C. and a load of 2160 g is 1 g / 10 minutes, and more preferably 3 g / 10 minutes. On the other hand, the upper limit of MFR is preferably 15 g / 10 minutes, more preferably 10 g / 10 minutes, and even more preferably 6 g / 10 minutes. By using EVOH (A) having such a melt viscosity, melt moldability, retort resistance, and the like can be further improved. The value of MFR in the present specification can be measured according to ASTM D1238.

In the resin composition of the present invention, the lower limit of the content of EVOH (A) is 55 parts by mass, preferably 60 parts by mass, with respect to 100 parts by mass of the total amount of EVOH (A) and PA (B). Parts by mass are more preferred, and 70 parts by mass is even more preferred. On the other hand, the upper limit of the content is 99 parts by mass, preferably 95 parts by mass, more preferably 93 parts by mass, and particularly preferably 90 parts by mass. When the content of EVOH (A) is within the above range, gas barrier property, retort resistance, long-run property and the like can be further improved in a well-balanced manner.

<PA (B)>
The resin composition of the present invention can exhibit good retort resistance by containing PA (B). PA (B) is a polymer having an amide bond in the main chain. Examples of PA (B) include polymerid (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecaneamide (nylon 11), polylauryl. Lactum (nylon 12), polyethylene diamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), poly Hexamethylene dodecamide (nylon 612), polyoctamethylene adipamide (nylon 86), polydecamethylene adipamide (nylon 106), caprolactam / lauryllactam copolymer (nylon 6/12), caprolactam / ω-aminononane Acid copolymer (nylon 6/9), caprolactam / hexamethylene diammonide adipate copolymer (nylon 6/66), lauryl lactam / hexamethylene diammonium adipate copolymer (nylon 12/66), ethylene diammonium adipate / Hexamethylene diammonide adipate copolymer (nylon 26/66), caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sevacate copolymer (nylon 6/66/610), ethylene diammonium adipate / hexamethylene di Ammonium adipate / hexamethylene diammonium sevacate copolymer (nylon 26/66/610), polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene terephthalamide (nylon 6T), hexamethylene isophthalamide / hexamethylene terephthalamide Copolymer (Nylon 6I / 6T), 11-Aminoundecaneamide / Hexamethylene terephthalamide copolymer, Polynonamethylene terephthalamide (Nylon 9T), Polydecamethylene terephthalamide (Nylon 10T), Polyhexamethylenecyclohexylamide, Examples thereof include polynonamethylenecyclohexylamides or those obtained by modifying these polyamides with aromatic amines such as methylenebenzylamine and metaxylene diamine. In addition, metaxylylene diammonium adipate and the like can also be mentioned.

Among them, a polyamide mainly composed of caproamide is preferable from the viewpoint of gas barrier property, retort resistance, long-run property at the time of melt molding, and specifically, 75 mol% or more of the constituent units of the polyamide is a caproamide unit. preferable. Of these, nylon 6 and nylon 6/66 are preferable from the viewpoints of good compatibility with EVOH (A) and excellent retort resistance.

PA (B) can be obtained by melt polymerization, interfacial polymerization, solution polymerization, bulk polymerization, solid phase polymerization, or a combination thereof.

The lower limit of the melting point TmB of PA (B) is preferably 190 ° C., more preferably 200 ° C., even more preferably 205 ° C., and particularly preferably 210 ° C. When the melting point TmB of PA (B) is set to be equal to or higher than the above lower limit, the retort resistance and the like can be further improved. On the other hand, the upper limit of the melting point TmB is preferably, for example, 250 ° C., more preferably 230 ° C., and even more preferably 225 ° C. When the melting point TmB is 250 ° C. or lower, long-running property and film thickness stability at the time of melt molding can be further improved.

In the resin composition of the present invention, the lower limit of the content of PA (B) is 1 part by mass with respect to 100 parts by mass of the total amount of EVOH (A) and PA (B), preferably 5 parts by mass, and 7 By mass is more preferred, and 10 parts by mass is particularly preferred. By setting the content of PA (B) to 1 part by mass or more, retort resistance and the like can be improved. On the other hand, the upper limit of the content is 45 parts by mass, preferably 40 parts by mass, more preferably 30 parts by mass, further preferably 20 parts by mass, and particularly preferably 17 parts by mass. When the content of PA (B) is 45 parts by mass or less, it tends to show good retort resistance while maintaining gas barrier properties and long-run properties during melt molding.

In the resin composition of the present invention, it is preferable that PA (B) is present in a finely dispersed state in the phase of EVOH (A). In such a state, gas barrier property, retort resistance, long-run property, hue, film thickness stability, and the like tend to be further improved. The fact that PA (B) is present in a finely dispersed state in the phase of EVOH (A) means that the average particle size of PA (B) is less than 0.05 μm in the method described in Examples described later. Say that. The average particle size of PA (B) means the average value of the diameters of 10 arbitrary PA (B) particles. The diameter of each PA (B) particle means an average value of the diameter and the diameter orthogonal to the diameter. The dispersed state of PA (B) can be adjusted by adjusting the mixing ratio of each component and the kneading conditions.

<Alkaline earth metal salt (C)>
The resin composition of the present invention contains 10 to 200 ppm of an alkaline earth metal salt (C) in terms of metal atoms with respect to the total amount of EVOH (A) and PA (B), so that the long-run property at the time of melt molding can be improved. It will be good. As the metal constituting the alkaline earth metal salt (C), magnesium and calcium are preferable, and magnesium is more preferable from the viewpoint of better long-running property at the time of melt molding.

Examples of the alkaline earth metal salt (C) include organics such as aliphatic carboxylic acids, aromatic carboxylic acids, aliphatic dicarboxylic acids, aromatic dicarboxylic acids, tricarboxylic acids, tetracarboxylic acids, hydroxycarboxylic acids, ketodicarboxylic acids, and amino acids. Acid salts; Examples include salts of inorganic acids such as sulfuric acid, sulfite, carbonic acid, and phosphoric acid. Of these, an aliphatic carboxylic acid metal salt is preferable, and an aliphatic carboxylic acid metal salt having 6 or less carbon atoms is more preferable from the viewpoint of compatibility with EVOH (A) and the like. Examples of fatty acids include saturated fatty acids such as formic acid, acetic acid, propionic acid, butyric acid and caproic acid; and unsaturated fatty acids such as acrylic acid and methacrylic acid. Among them, saturated fatty acids having 1 to 3 carbon atoms are preferable, and acetic acid is more preferable, from the viewpoint of compatibility with EVOH (A) and the like.

In the resin composition of the present invention, the metal constituting the alkaline earth metal salt (C) may form a salt as a counter cation of the anion constituting the alkaline earth metal salt (C), or EVOH ( A salt may be formed as a counter cation of the alkoxide of A).

The lower limit of the content of the alkaline earth metal salt (C) in the resin composition of the present invention is 10 ppm in terms of metal atoms with respect to the total amount of EVOH (A) and PA (B), preferably 20 ppm, and 30 ppm. Is more preferable. If the content of the alkaline earth metal salt (C) is less than 10 ppm, the long-run property during melt molding and the film thickness stability during film formation tend to deteriorate. On the other hand, the upper limit of the content is 200 ppm, preferably 150 ppm, and more preferably 100 ppm. If the content of the alkaline earth metal salt (C) exceeds 200 ppm, the hue and film thickness stability during continuous film formation tend to deteriorate.

In the resin composition of the present invention, it is preferable that the alkaline earth metal salt (C) is uniformly dispersed throughout the resin composition. Further, the alkaline earth metal salt (C) may be used alone or in combination of two or more.

<Alkali metal salt (D)>
By containing the alkali metal salt (D) in a specific ratio with respect to the alkaline earth metal salt (C), the resin composition of the present invention can remarkably improve the long-run property during melt molding. Examples of the alkali metal constituting the alkali metal salt (D) include sodium and potassium, and sodium is more preferable from the viewpoint of long-running property during melt molding and the like.

The alkali metal salt (D) is a salt of an organic acid such as an aliphatic carboxylic acid, an aromatic carboxylic acid, an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid, a tricarboxylic acid, a tetracarboxylic acid, a hydroxycarboxylic acid, a ketodicarboxylic acid, or an amino acid. ; Examples include salts of inorganic acids such as sulfuric acid, sulfite, carbonic acid and phosphoric acid. Of these, an aliphatic carboxylic acid metal salt is preferable, and an aliphatic carboxylic acid metal salt having 6 or less carbon atoms is more preferable from the viewpoint of compatibility with EVOH (A) and the like. Examples of fatty acids include saturated fatty acids such as formic acid, acetic acid, propionic acid, butyric acid and caproic acid; and unsaturated fatty acids such as acrylic acid and methacrylic acid. Among them, saturated fatty acids having 1 to 3 carbon atoms are preferable, and acetic acid is more preferable, from the viewpoint of compatibility with EVOH (A) and the like.

In the resin composition of the present invention, the metal constituting the alkali metal salt (D) may form a salt as a counter cation of the anion constituting the alkali metal salt (D), or the alkoxide of EVOH (A) may be formed. A salt may be formed as a counter cation of.

The lower limit of the content of the alkali metal salt (D) in the resin composition of the present invention is 10 ppm in terms of metal atoms with respect to the total amount of EVOH (A) and PA (B), more preferably 100 ppm, and 200 ppm. More preferably, 250 ppm is particularly preferable. When the content of the alkali metal salt (D) is 10 ppm or more, the long-run property at the time of melt molding can be improved. On the other hand, the upper limit of the content is preferably 2000 ppm, more preferably 1500 ppm, further preferably 1000 ppm, and particularly preferably 700 ppm. When the content of the alkali metal salt (D) is 2000 ppm or less, deterioration of hue and film thickness stability during continuous melt molding tends to be suppressed. Further, when the content of the alkali metal salt (D) is not more than the above upper limit, the hue of the resin composition of the present invention and the obtained molded product can be improved and yellowing can be suppressed.

In the resin composition of the present invention, it is preferable that the alkali metal salt (D) is uniformly dispersed throughout the resin composition. Further, the alkali metal salt (D) may be used alone or in combination of two or more.

<Mixing ratio>
The resin composition of the present invention has a mass ratio (A / B) of EVOH (A) and a polyamide resin (B) of 55/45 to 99/1, and thus has good gas barrier properties, retort resistance, and melt molding. Shows the long-running property of time. The lower limit of the mass ratio (A / B) is preferably 60/40, more preferably 70/30, even more preferably 80/20, and particularly preferably 83/17. The upper limit of the mass ratio (A / B) is preferably 99/1, more preferably 95/5, further preferably 93/7, and particularly preferably 90/10.

In the resin composition of the present invention, the ratio (Dm / Cm) of the metal atom-equivalent mass (Dm) of the alkali metal salt (D) to the metal atom-equivalent mass (Cm) of the alkaline earth metal salt (C) is 1 to 1. When it is 20, the long-running property, hue, film thickness stability, etc. at the time of melt molding can be remarkably improved. The mass ratio (Dm / Cm) is preferably 2.0 or more, more preferably 3.0 or more, further preferably 4.0 or more, and particularly preferably 5.2 or more. The mass ratio (Dm / Cm) is preferably 20 or less, more preferably 15 or less, and even more preferably 12 or less.

In the resin composition of the present invention, the alkaline earth metal salt (C) is well dispersed in the resin composition, so that the long-run property and the film thickness stability tend to be good. Whether or not the alkaline earth metal salt (C) has good dispersibility in the resin composition of the present invention can be determined by satisfying the following requirement 1. When the resin composition of the present invention does not satisfy the following requirement 1, the dispersibility of the alkaline earth metal salt (C) is insufficient, and the effect of improving the long-running property and the film thickness stability is insufficient.
(Requirement 1)
When a film having a thickness of 20 μm made of the resin composition of the present invention is continuously formed at 230 ° C. using a single-screw extruder, it is visually observed on the film formed one hour after the start of film formation. Of the 10 defects, the number of defects having an alkaline earth metal concentration of 0.1 at% or more is less than 2. The defect (defect point) in the present specification refers to a point-like object (dot-like region) observed as a point whose brightness is different from that of the surroundings when the film is transparent to light. The drawback is that it is formed by unmelted resin (resin that remains undissolved during film formation), deteriorated resin, non-uniform composition distribution due to foreign matter contamination or agglomerates, etc. It is different from the voids that occur and the small holes (pinholes) that occur in the film.
As a specific measurement method of the above requirement 1, the method described in the examples is adopted.

The resin composition of the present invention tends to satisfy Requirement 1 by producing it using an aqueous solution containing an alkaline earth metal salt (C) as described in the method for producing a resin composition described later. ..

<Other ingredients>
The resin composition of the present invention includes other resins other than EVOH (A) and PA (B), such as polyolefins, and additives (resins) other than alkali metal salts (D) and alkaline earth metal salts (C). Ingredients other than) may be further contained as other ingredients.

However, the lower limit of the ratio of the total amount of EVOH (A) and PA (B) to the total resin components in the resin composition of the present invention is preferably 90% by mass, more preferably 97% by mass, still more preferably 99% by mass. .. As described above, when the resin component is substantially composed of only EVOH (A) and PA (B), the long-run property, gas barrier property, and retort resistance at the time of melt molding can be further improved.

Examples of the additive include known additives such as plasticizers, fillers, antiblocking agents, antioxidants, colorants, antistatic agents, ultraviolet absorbers, lubricants, and desiccants. However, the content of the additive (component other than the resin) is preferably 2 parts by mass or less, more preferably 1 part by mass or less, based on 100 parts by mass of the total amount of EVOH (A) and PA (B). When the content of the additive is reduced, long-running property, gas barrier property, retort resistance, hue, film thickness stability and the like at the time of melt molding can be improved.

The shape of the resin composition of the present invention is not particularly limited, but is usually in the form of pellets. Further, the resin composition of the present invention is usually a dried product. The water content of the resin composition of the present invention with respect to all the resin components may be, for example, 10% by mass or less, 1% by mass or less, or 0.1% by mass or less. The resin composition of the present invention can be suitably used as a melt molding material such as a packaging material.

<Manufacturing method of resin composition>
The method for producing the resin composition of the present invention is not particularly limited. For example, a production method including a step of dry-blending EVOH (A) and PA (B) and a step of melt-kneading the mixture obtained by the above-mentioned dry blend can be mentioned. Above all, in order to further enhance the thermal stability, gas barrier property and retort resistance, a step of dry blending EVOH (A) and PA (B) and a step of melt-kneading the mixture obtained by the above dry blend are provided. The manufacturing method is preferable.

The EVOH (A) and PA (B) used in each of the above dry blending steps and the melt-kneading step are usually pellets, respectively. As a method for incorporating the alkaline earth metal salt (C) and the alkali metal salt (D) into these pellets, an aqueous solution containing the alkaline earth metal salt (C) and the alkali metal salt (D) prepared in advance is sufficient. Those that have been soaked or contacted for a period of time, for example, 1 second to 1 day, can be used. Further, in the melt-kneading step, melt-kneading can be performed together with an aqueous solution containing an alkaline earth metal salt (C) and an alkali metal salt (D) prepared in advance. That is, a step of immersing at least one of EVOH (A) and PA (B) in an aqueous solution containing an alkaline earth metal salt (C) and an alkali metal salt (D), and melting containing EVOH (A) and PA (B). The resin composition contains the alkaline earth metal salt (C) and the alkaline metal salt (D) by a step of mixing the resin with an aqueous solution containing the alkaline earth metal salt (C) and the alkaline metal salt (D). be able to.

Specific manufacturing methods include the following manufacturing method 1 and manufacturing method 2.
Production method 1: A step of immersing at least one of EVOH (A) and PA (B) in an aqueous solution containing an alkaline earth metal salt (C) and an alkali metal salt (D), and a step of immersing EVOH (A) and PA (B). ) And a step of melt-kneading EVOH (A) and PA (B) in this order.
Production method 2: A step of dry-blending EVOH (A) and PA (B) and a step of melt-kneading the mixture obtained by the dry blend are included in this order, and the above-mentioned melt-kneading step is EVOH (A). ) And a molten resin containing PA (B) and an aqueous solution containing an alkaline earth metal salt (C) and an alkali metal salt (D).

On the other hand, when the resin composition is produced by the step of dry-blending EVOH (A), PA (B), alkaline earth metal salt (C) and alkali metal salt (D), the alkaline earth metal salt (C) is particularly produced. ) Deteriorates and tends not to satisfy the above requirement 1, and the effect of improving long-running property and film thickness stability cannot be expected.

The melt-kneading can be performed by a known device such as a single-screw extruder or a twin-screw extruder. Further, in each melt-kneading step, the resin composition of the present invention can be obtained as pellets by melt-extruding and pelletizing with a single-screw extruder, a twin-screw extruder or the like.

<Molded body, etc. and manufacturing method of molded body>
The molded product of the present invention comprises the resin composition of the present invention, and is usually a melt molded product of the resin composition of the present invention. The method for producing a molded product of the present invention includes a step of melt-molding the resin composition of the present invention.

That is, the resin composition of the present invention can be molded into a molded product such as a film, a container, or other packaging material (for foods, pharmaceuticals, etc.) by melt molding. When performing melt molding, the resin composition of the present invention may be melt-molded, or EVOH (A) and PA (B) may be dry-blended and directly melt-molded. The resin composition of the present invention has good gas barrier properties and retort resistance, and is also excellent in long-run properties during melt molding, hue and film thickness stability during continuous molding. Therefore, a molded product such as a film, which is a melt-molded product of the resin composition of the present invention, is suitable for use as a retort-treated packaging material or a boil-treated packaging material. In the present specification, the term "film" is not particularly limited in thickness, and is a concept including what is called a sheet.

The molded product (film or the like) of the present invention may be a secondary processed molded product. Examples of such a secondary processed product include a retort pouch, a thermoformed container, a lid material for a thermoformed container, a food packaging container such as a shrink container, and other packaging containers. When the molded product of the present invention is a film, the film may be a single layer or a multi-layered film, but contains a hydrophobic thermoplastic resin for the purpose of preventing deterioration of the gas barrier performance of the resin composition due to moisture. It is preferably used as a multi-layer structure with layers. Examples of the hydrophobic thermoplastic resin include a polyolefin resin (polyethylene resin, polypropylene resin, etc.), a grafted polyolefin resin graft-modified with an unsaturated carboxylic acid or an ester thereof, a halogenated polyolefin resin, an ethylene-vinyl acetate copolymer resin, and the like. Ethylene-acrylic acid copolymer resin, ethylene-acrylic acid ester copolymer resin, polyester resin, polyamide resin, polyvinyl chloride resin, polyvinylidene chloride resin, acrylic resin, polystyrene resin, vinyl ester resin, ionomer, polyester elastomer, Examples thereof include polyurethane elastomers, aromatic or aliphatic polyketones. Of these, polyolefin resins are preferable, and polyethylene resins and polypropylene resins are even more preferable, in terms of mechanical strength and moldability. Further, in addition to these resins, a multi-layer structure may be used in combination with paper, metal foil, woven fabric, non-woven fabric, metal cotton strip, wood surface, aluminum or silica vapor deposition.

As the layer structure of the multilayer structure, the layer obtained from the resin composition of the present invention is F, the layer composed of the hydrophobic thermoplastic resin is A, and the hydrophobic thermoplastic resin modified with unsaturated carboxylic acid or a derivative thereof. When the layer composed of MA is represented by MA, the following layer structure can be exemplified. As for the layer structure, the one on the left side indicates that the layer is on the outside (the side exposed to the external environment). The layer MA made of a hydrophobic thermoplastic resin modified with an unsaturated carboxylic acid or a derivative thereof is used as an adhesive resin layer and also as an outer layer.
2-layer MA / F
3 layers A / MA / F, MA / F / MA, F / MA / F, A / F / A
4 layers A / MA / F / MA, MA / F / MA / F
5 layers F / MA / A / MA / F, A / MA / F / MA / A
MA / F / MA / F / MA, A / MA / F / MA / F
A / F / A / MA / A
6 layers A / MA / F / MA / A / MA
7 layers A / MA / F / MA / F / MA / A

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples shown below. The measurement, calculation and evaluation methods were as follows.

<Resin used>
・ EVOH (A) (manufactured by Kuraray Co., Ltd.)
EVOH (A-1): "EVOH (registered trademark) L171B" (EVOH, ethylene unit content 27 mol%, MFR (210 ° C., 2160 g load) 4.0 g / 10 minutes, melting point 191 ° C.)
EVOH (A-2): "EVOH (registered trademark) F171B" (EVOH, ethylene unit content 32 mol%, MFR (210 ° C., 2160 g load) 3.7 g / 10 minutes, melting point 183 ° C.)
・ PA (B) (manufactured by Ube Industries, Ltd.)
PA (B-1): "UBE NYLON SF1018A" (nylon 6)
PA (B-2): "UBE NYLON 1024B" (nylon 6)
PA (B-3): "UBE NYLON 1030B" (nylon 6)
PA (B-4): "UBE NYLON 7024B" (nylon 6,12)
PA (B-5): "UBE NYLON 5023B" (nylon 6,66)

<Evaluation method>
(1) Quantification of Alkali Earth Metal and Alkali Metal Ion 0.5 g of the resin composition pellets obtained in each Example and Comparative Example was added to a pressure-resistant container manufactured by Teflon (registered trademark) manufactured by Actac, and Wako Pure Chemical Industries, Ltd. 5 mL of the company's precision analytical alkali was added. After leaving it for 30 minutes, cover the container with a cap lip with a rupture disc, and disassemble it under the conditions of 150 ° C for 10 minutes and then 180 ° C for 10 minutes with the microwave high-speed decomposition system "Speedwave MWS-2" manufactured by Actac. Processing was performed. When the decomposition of the dried EVOH pellets was insufficient, the treatment conditions were adjusted as appropriate. The mixture was diluted with 10 mL of ion-exchanged water, all the solutions were transferred to a 50 mL volumetric flask, and the volume was adjusted with ion-exchanged water to obtain a decomposition solution.
The above decomposition solution is quantitatively analyzed at each observation wavelength shown below using an ICP emission spectroscopic analyzer "Optima 4300 DV" manufactured by PerkinElmer Japan, and the amount of each alkaline earth metal and alkali metal ion. Was quantified.
Mg: 285.213 nm
Ca: 317.933 nm
Na: 589.592 nm
K: 766.490 nm

(2) Oxygen Permeation Rate For the monolayer films having a thickness of 20 μm obtained in each Example and Comparative Example, MOCON INC. JIS K 7126 under the conditions of 20 ° C. and 65% RH using the oxygen permeability measuring device "OX-TRAN2 / 20 type" (detection limit value 0.01 cc · 20 μm / (m ^{2 · day · atm)) manufactured by JIS K 7126.} The measurement was performed according to the method described in (Isometric method). The oxygen barrier property was judged according to the following criteria. When the judgment is A to B, the gas barrier property is good.
Judgment: Criteria A: Less than 0.3 B: 0.3 or more and less than 0.5 C: 0.5 or more (Unit is cc, 20 μm / m ² , day, atm)

(3) Retort resistance Single-layer film with a thickness of 20 μm, biaxially stretched nylon 6 film (“Emblem ONBC” manufactured by Unitica, thickness 15 μm) and unstretched polypropylene film (Mitsui Kagaku Tohcello) obtained in each Example and Comparative Example. "Tosero CP" manufactured by the company, thickness 50 μm) is cut to A4 size, and dry laminating adhesive is applied to both sides of the single layer film so that the outer layer becomes a nylon 6 film and the inner layer becomes a non-stretched polypropylene film. Dry laminating was carried out and dried at 80 ° C. for 3 minutes to obtain a transparent laminated film consisting of three layers. As the adhesive for dry lamination, "Takelac A-520" of Mitsui Chemicals, Inc. was used as a main agent, "Takenate A-50" of Mitsui Chemicals, Inc. was used as a curing agent, and ethyl acetate was used as a diluent. The amount of the adhesive applied was 4.0 g / m ^2, and after laminating, curing was carried out at 40 ° C. for 3 days.

Using the obtained laminated film, a pouch having an inner dimension of 12 cm × 12 cm sealed on all sides was produced. The contents were water. This was retorted at 120 ° C. for 120 minutes using a retort device (high temperature and high pressure cooking sterilization tester "RCS-40RTGN" manufactured by Hisaka Works, Ltd.). After the retort treatment, the surface water was wiped off and left in a room at 20 ° C. and 65% RH for one day, and then the appearance characteristics were judged according to the following criteria as an evaluation of the retort resistance. When the evaluation is from A to C, the retort resistance is good.
Judgment: Criteria A: No whitening B: Streaky whitening is seen C: Slightly whitening D: Whitening

(4) Long-run property Using the resin compositions obtained in Examples and Comparative Examples, a single-screw extruder (Toyo Seiki Seisakusho Co., Ltd., D2020, D (mm) = 20, L / D = 20, compression ratio = 3 A single-layer film having a thickness of 20 μm was continuously produced by (5, screw: full flight). The extrusion conditions are as follows.
Extrusion temperature: 230 ° C
Dice width: 30 cm
Pick-up roll temperature: 80 ° C
Screw rotation speed: 40 rpm
Pick-up roll speed: 3.0 m / min

A 10 cm × 10 cm film produced after a specific time described later from the start of film production was sampled, and the number of lumps of 100 μm or more was visually counted. The long run property was judged from the number of lumps according to the following criteria.
Judgment: Criteria A: 50 pieces / 100 cm ² or less B: 50 pieces / 100 cm ^{more than 2} , 100 pieces / 100 cm ² or less C: 100 pieces / 100 cm ^{more than 2} , 150 pieces / 100 cm ² or less D: 150 pieces / 100 cm ² More, 200 pieces / 100 cm ² or less E: 200 pieces / 100 cm more than ²

(5) Hue The single-layer films produced in Examples and Comparative Examples were continuously formed for 12 hours, and the single-layer film produced 12 hours after the start of film formation was wound around a paper tube to color the end face of the film. The degree was judged with the naked eye according to the following criteria.
Judgment: Criteria A: No yellowing B: Slight yellowing C: Slight yellowing D: Yellowing

(6) Film Thickness Stability With respect to the single-layer films produced in Examples and Comparative Examples, continuous film formation was performed for 12 hours, and the thickness of the single-layer films produced 1 hour and 12 hours after the start of film formation was measured. Then, the reduction rate of the film thickness was calculated using the following formula (1), and the film thickness stability was determined according to the following criteria.
Reduction rate = {1- (thickness of single-layer film produced 12 hours after the start of film formation (μm)) / (thickness of single-layer film produced 1 hour after the start of film formation (μm))} × 100% ( 1)
Judgment: Criteria A: Decrease rate less than 10% B: Decrease rate 10% or more and less than 20% C: Decrease rate 20% or more and less than 30% D: Decrease rate 30% or more

(7) Observation with Transmission Electron Microscope (TEM) The resin composition was embedded in epoxy resin, and a section in the transverse direction was prepared by an ultramicrotome. The obtained cross section was brought into contact with a 5% phosphotung acid aqueous solution for 5 minutes, dried, and then observed using a transmission electron microscope "JEM2100" manufactured by JEOL Ltd. at an observation magnification of 5000 times. When the average particle size of PA (B) observed from the image was less than 0.05 μm, it was determined to be fine dispersion.

(8) Evaluation of Dispersibility of Alkaline Earth Metal Salt (C) Continuous film formation was performed under the same conditions as in the above (4) Evaluation of long-run property, and 1 m of the film formed 1 hour after the start of film formation was cut out. It was divided into 10 pieces every 10 cm in the length direction. The largest defects visually observed in each division were cut out with a microtome in the transverse direction, and sections in which the cross sections of the defects were exposed were prepared. For the defective part of the obtained cross section, the concentration of alkaline earth metal atoms was calculated using a scanning electron microscope "S-3000N" with EDX (Energy Dispersive X-ray Analyzer) manufactured by Hitachi, Ltd., and the alkali The number of defects with an earth metal atomic concentration of 0.1 at% or more was counted. When there was a division without any visually observed defects, the film was further cut out and classified in the same manner, and the process was repeated until the number of defects to be measured reached 10.
Judgment: Criteria A: 0 to 1 B: 2 or more

[Example 1]
After dry-blending each pellet so that EVOH (A-1) is 90 parts by mass as EVOH (A) and PA (B-1) is 10 parts by mass as PA (B), manufactured by Japan Steel Works, Ltd. It was supplied to a twin-screw extruder "TEX30α" (screw diameter 30 mm). Further, in the twin-screw extruder, an aqueous solution of magnesium acetate as an alkaline earth metal salt (C) having a concentration of 1.5 g / L and an aqueous solution of sodium acetate as an alkali metal salt (D) having a concentration of 7.5 g / L was used. Add with a liquid addition pump, and melt using a screw with a forward kneading disk having L (screw length) / D (screw diameter) = 3 as a screw configuration on the downstream side of the addition. Melt extrusion was performed under the conditions of a temperature of 220 to 230 ° C. and an extrusion rate of 20 kg / hr. Then, the extruded strands were cooled and solidified in a cooling tank and then cut to obtain resin composition pellets.

Using the obtained resin composition pellets, in a single-screw extruder (Toyo Seiki Seisakusho Co., Ltd., D2020, D (mm) = 20, L / D = 20, compression ratio = 3.5, screw: full flight). A 20 μm monolayer film was prepared. The extrusion conditions are as follows.
Extrusion temperature: 230 ° C
Dice width: 30 cm
Pick-up roll temperature: 80 ° C
Screw rotation speed: 45 rpm
Pick-up roll speed: 3.4 m / min

With respect to the obtained resin composition pellets and monolayer film, quantification of alkaline earth metals and alkali metal ions, measurement of oxygen permeability, and retort resistance according to the methods described in (1) to (6) and (8) above. The properties, long-running properties, hue, film thickness stability, and dispersibility of the alkaline earth metal salt (C) were evaluated. In addition, (4) continuous film formation time for evaluation of long-run property was set to 8 hours. The results are shown in Table 1.

[Examples 2 to 6, Comparative Examples 1 and 2]
Resin composition pellets in the same manner as in Example 1 except that the concentration of the aqueous solution was adjusted so that the contents of the alkaline earth metal salt (C) and the alkali metal salt (D) were as shown in Table 1. And a single-layer film was prepared and evaluated. The results are shown in Table 1.

[Example 7]
Resin in the same manner as in Example 1 except that the contents of EVOH (A), PA (B), alkaline earth metal salt (C) and alkali metal salt (D) were changed as shown in Table 2. Composition pellets and monolayer films were prepared.

With respect to the obtained resin composition pellets and monolayer film, quantification of alkaline earth metals and alkali metal ions, measurement of oxygen permeability, and retort resistance according to the methods described in (1) to (6) and (8) above. The properties, long-running properties, hue, film thickness stability, and dispersibility of the alkaline earth metal salt (C) were evaluated. In addition, (4) continuous film formation time for evaluation of long-run property was set to 6 hours. The results are shown in Table 2.

[Examples 8 to 25, Comparative Examples 3 to 6, 8, 9]
The same as in Example 7 except that the types and contents of EVOH (A), PA (B), alkaline earth metal salt (C) and alkali metal salt (D) were changed as shown in Table 2. Resin composition pellets and monolayer films were prepared and evaluated. The results are shown in Table 2.

[Comparative Example 7]
EVOH (A-1) is supplied as EVOH (A) to the twin-screw extruder, and the magnesium acetate aqueous solution is prepared as the alkaline earth metal salt (C) in the twin-screw extruder so that the magnesium concentration becomes as shown in Table 2. After being added to the film with a liquid addition pump, it was heated and melted in the compression section of the extruder, and supplied so as to form a sheath layer of a multilayer die under the condition of 170 kg / hr. Subsequently, PA (B-1) as PA (B) was heated and melted at 240 ° C. by a single-screw melt extruder and supplied to a multilayer die at 30 kg / hr so as to form a core layer. Multi-layered strands were discharged from the multi-layer die, and the discharged strands were cooled and solidified in a cooling tank and then cut to produce multi-layer pellets. The obtained pellet was a multi-layer pellet having PA (B) in the core layer and EVOH (A) in the sheath layer, and the mass ratio of the core layer to the sheath layer was 15/85.

Using the obtained multilayer pellets, a single-layer film was prepared under the same conditions as in Example 1. The obtained multilayer pellets and monolayer films were evaluated in the same manner as in Example 7. The results are shown in Table 2.

[Example 26]
In the same manner as in Example 1 except that the contents of EVOH (A), PA (B), alkaline earth metal salt (C) and alkaline earth salt (D) were changed as shown in Table 3. Resin composition pellets and monolayer films were prepared.

With respect to the obtained resin composition pellets and monolayer film, quantification of alkaline earth metals and alkali metal ions, measurement of oxygen permeability, and retort resistance according to the methods described in (1) to (6) and (8) above. The properties, long-running properties, hue, film thickness stability, and dispersibility of the alkaline earth metal salt (C) were evaluated. In addition, (4) continuous film formation time for evaluation of long-run property was set to 4 hours. The results are shown in Table 3.

[Examples 27 to 31, Comparative Examples 10 and 11]
The resin composition pellets and the resin composition pellets and the same as in Example 26, except that the concentration of the aqueous solution was adjusted so that the contents of the alkaline earth metal salt (C) and the alkali metal salt (D) were as shown in Table 1. A single-layer film was prepared and evaluated. The results are shown in Table 3.

[Comparative Example 12]
Instead of adding magnesium acetate with a liquid addition pump, when 80 parts by mass of EVOH (A-1) and 20 parts by mass of PA (B-1) are dry-blended, magnesium acetate powder is dry-blended at the same time. Resin composition pellets and a single-layer film were prepared and evaluated in the same manner as in Example 26 except that magnesium acetate was added. The results are shown in Table 3.

As a result of TEM observation of the monolayer films of Examples 1, 7 and 26 according to the above evaluation method (7), it was confirmed that PA (B) was finely dispersed in EVOH (A). ..

The resin composition of the present invention can be suitably used as a packaging material, particularly a retort-treated packaging material or a boil-treated packaging material.

Claims (13)

It contains an ethylene-vinyl alcohol copolymer (A), a polyamide resin (B), an alkaline earth metal salt (C) and an alkali metal salt (D), and contains an ethylene-vinyl alcohol copolymer (A) and a polyamide resin (B). ) Is 55/45 to 99/1, and the alkaline earth metal salt (C) with respect to the total amount of the ethylene-vinyl alcohol copolymer (A) and the polyamide resin (B). ) Is contained in an amount of 10 to 200 ppm in terms of metal atom, and the ratio (Dm / Cm) of the mass (Dm) of the alkali metal salt (D) in terms of metal atom to the mass (Cm) of the alkaline earth metal salt (C) in terms of metal atom. ) Are 1 to 20, and the resin composition satisfies the following requirement 1.
(Requirement 1)
When a film having a thickness of 20 μm made of the resin composition is continuously formed at 230 ° C. using a single-screw extruder, it is visually observed in the film formed one hour after the start of film formation. Among the defects, the number of defects in which the concentration of the alkaline earth metal is 0.1 at% or more is less than two. The resin composition according to claim 1, wherein the metal constituting the alkaline earth metal salt (C) contains magnesium or calcium. The resin composition according to claim 1 or 2, wherein the metal constituting the alkali metal salt (D) contains sodium or potassium. The resin composition according to any one of claims 1 to 3, wherein the alkaline earth metal salt (C) is an aliphatic carboxylic acid alkaline earth metal salt having 6 or less carbon atoms. The resin composition according to any one of claims 1 to 4, wherein the alkali metal salt (D) is an aliphatic carboxylic acid alkali metal salt having 6 or less carbon atoms. The resin composition according to any one of claims 1 to 5, wherein the polyamide resin (B) contains nylon 6. The resin composition according to any one of claims 1 to 6, which is in the form of pellets. A molded product containing the resin composition according to any one of claims 1 to 7. The molded product according to claim 8, which is a film. The molded article according to claim 8 or 9, which is a retort-treated packaging material or a boil-treated packaging material. The secondary processed product of the molded product according to any one of claims 8 to 10. A step of immersing at least one of the ethylene-vinyl alcohol copolymer (A) and the polyamide resin (B) in an aqueous solution containing an alkaline earth metal salt (C) and an alkali metal salt (D), and an ethylene-vinyl alcohol co-weight. The method for producing a resin composition according to any one of claims 1 to 7, which comprises a step of melt-kneading the coalescence (A) and the polyamide resin (B). A claim comprising a step of mixing a molten resin containing an ethylene-vinyl alcohol copolymer (A) and a polyamide resin (B) with an aqueous solution containing an alkaline earth metal salt (C) and an alkali metal salt (D). The method for producing a resin composition according to any one of 1 to 7.